Control mechanism for calculating machines



1 2 July 9 7 J. H. F. SILVER CONTROL MECHANISM FOR CALCULATING MACHINESMay 27. 1925 J. H. F. SILVER CONTROL MECHANISM FOR CALCULATING MACHINESJuly 26, 1927.

26 192 July 7 J. H; F. SILVER CONTROL MECHANISM FOR CALCULATING MACHINESFiled May 27. 1925 5 Sheot s- Sheet 3 July 1927' J. H. F. SILVER CONTROLMECHANISM FOR CALCULATING MACHINES gvwentoz d. [6/1 Vf/P,

Sheets-Shoot 4 .Filed May 2'7. 1925 July 1927' J. H. F. SILVER CONTROLMECHANISM FOR CALCULATING MACHINES Filed May 27. 1925 5 Sheets-Sheet 5llilu Patented July 26, 1927.

UNETED STATES JOHN H. F. SILVER, F PHILADELBHIA, PENNSYLVANIA.

CONTROL MECHANISM FOR ALC LATING MA HINES.

Application filed May 27, 1925. Serial No. 33,192.

My invention relates to calculating and adding machines, one of theimportant objects, briefly stated, residing in a very simple, highlyefiective and practicable type or attachment which may be readily placedupon or built into the existin calculating machines of the type generaly known as the key'driven comptometer, for the purpose of warning theoperator bynot only a visible signal but by means of an audible signalthe instant the stroke of any one of the keys has not been completed, aswhen the key is but partially depressed.

I am aware of the fact that various at tempts have been made to remedythis very serious difficulty in connection with calculating machines inan vefl'ort to assist the operator to continue his calculations withoutthe necessity of cancelling and repeatsoing. a

As it is well known to those familiar with the art, when a mistake ismade, as when a key has; not been'fully depressed, the clean ing levermust be pulled forward for resetting all of the keys to zero in thatparticu lar column. F or this reaspn,"operators of i this type "ofmachi'n'e have I found it simpler and faster, on'small calculations', tocancel and go over the problem r' ther than to'sto'p and make thenecessary correction. I

yVVith my improved attachment, I" have provided means ifor automatically"locking every key in all ofthe columns simultaneously. In this'manner,it will be readily 35 understood theoperator-is prevented fromdepressing keys 'of'columns other than ,the one injvhich the partialstroke was made, as, for instance, in'the process of multiplying; and,should the-operator fail to hear the audible -signal, he' 'may readilysee at a glance, the particular key which was inadvertently partiallydepressed.

In the drawings:

Figure l'is a side elevation of a calculat-' clearness and illustratingthe key in its normal or raised position;

Figure 5 is asimilar view showing the key but partially depressed andlocked;

Figure'ti sho s a similar viewbutillustrates the location of the severalparts as when the key is fully depressed and ready to be turned to'itsinitial or normal position:

Figure 7 isfa horizontal; sectional view taken on the line 7-7 of Figure6; Figure 8- illust rates a viewi'n perspective of one of thekey-'sillustrating my improvenient;" f'

igur'e" 9 is a transverse sectional vie taken on the line 9''9 of Figure4;

, Figure10is' a similar view taken through e Figure 'll is a view' inperspective of the frame work of my improved attachment clearlyillnstrating'the' bell'of the actuating niechanisnr'in connectiontherewith and f Figure l2 'is 'a'v'iewfin perspective 'on 'an enlargedscaleof's'everal of the details 'illustrating them intlieir co acting'positione My invention, in the form or'enibodim'ent "Susan is the fdrawings-aiid'briefly described, "comprises a pairf of "oppositely disposed-'jgilatesj'lQand llfwli'ich may bereadi ly'riv- "usages "at "12 orotherwise secured to the frame ofthfe e istiiijg ma'cliinelifl Theseplates, T10andll,'aie suitablylbraced-at'ftheir'outer "and: by meanso'fthe us'uala't'ubular Iiaernber, 13, with its assoeiated rod andfastening means. j It is w be nnderstood; 'of '-"cours'e,

i that if rnyattacliin'ent is to'be' built into the p 'ma'chine',"theplates,'1( and 11, would merely 'e bontinued rearwardtv from the sideplates of'tlie-inachin e; I 4

f" Inasmuch as" calculating machines of this a'rlelwell 'lirldivh'tqthosfamilial with ithe-fart I 'willfinak no attempt too into detail with theexisting or well ln'iown' maother than what is directly associated witlmy, improved "attachment" thereto." On

thello'we'r porti'onof'one of thelegsof the operating key; 15,1: rigidly se cure afpin, 16, "as isjclearly'illustratd in Figures 8, 9 and 10,'which 'isfextended"partially across the slot formed between the two'lower legs of the key, 15." The purpose of theupins, 16, is to engagethe1upper curved surface of hook ortions, 17 which may be either formedintegrally withithe upper edge of the usual key" fennel lever, 18, orwhich may be i tt' f't thre'tii iii. any other del 'titl iiiaiiner';

ti l

lVhen the keys are in their normal position, as is shown in Figure 4 ofthe accompanying drawings, the pins, 16, are free to more downwardlybeyond the hook portion, 17, the said keys being, held in their upperposition by means of the usual springs indicated as at 19 j The rear endof the key control lever, 18, is, of course, pivotally mounted to thelower end of the bell crank member, 22, as at 23. and the toothed arm,24:, is likewise mounted to the upper end of the member, 22, as at .25,they being held in their raised position by means of the coil spring,26, in the usual manner.

A relatively short distance below the pivot, 25, is loosely pivoted bymeans of a. rivet, 27, or the like, what might be termed a main controlpiece, 28, whichisprovided in its approximate center with an elongatedslot, 29. The upper and lower edges of. the main control piece, 28, areprovided with oppositely formed ratchet teeth, 30- and 31, for a purposeto be hereinafter described. A headed screw, 33-, is adapted to passthrough the slot, 29. and is secured to the plate, 10, by means of anut, 34, for the purposeof guiding themain control piece, 28, during theoperation of the keys, 15. The extreme rearward end of the main controlpiece, 28,; is rounded to form a. nose, -3 5 ,,-5and isfl'also providedatitsupper. edge adjacent to thelnose, 35,'with a cut-out portion, 36,to forma tooth. .3

.. To. the lock control lever,- 40, :and preferxa bly near the rearendlthereof, I provide an upwardly extending portion, 41,-,and arear-Wardly extending and relatively narrow warm, w c in es QY 11e --'orced-. -43 1A i go a ly, t nd g mu ets t g a y ifcrm s t emppe end .of-jthe arm, 42,; and-provided oir'its upgra! 1y formed with the lockcontrol leverAD. Upper and lower pawls, 48,and t9,:which, for clearness,may beytermedup pawls and down-pawls, are each ,pivotednat tlieir;,-re1r ends to the rods, and 5 l 'which extend tra v r y s th supp em immgot :myattachment; trymeans oiangnlarly hent l;ugsor ears,'52-and53. Asisobvious {from the: drawings, the pawl, 48, is adapted align withandtengage tihe,tootl i,, 30,. of

' the-main control piece,- .28,whereasthepawl,

49, is in alignment with and adapted'for eneagen'ientwith theplower setof, t e-etli, ;3l. The lugs or ears, 52, are provided witha slightlyelongated slot or opening, 54, for a purpose to be further described IThe rear end-of tlie rlown .-.pawl, 48, is formed with a downwardlyextending toe, 55, which is adapted for engagement with the extreme endof the arm, 56, which is,

in turn, bent downwardly forming an arm. 57. The members forming thearms, 56 and 57, are secured to a rod or shaft, 58, which isjoui'nl'iled ih tire-plates, l0 and 11, of the suppleumntatframe. Thelower extremity of the arm, 57', is slightly extended as at 5 for thepurposeoi forming a latch or (log, and is adapted to engage theoutwardly extending arm, 60, which is integrally formed with-the pawl,61. The pawl, 61, is secured to and carried by the transverselyextendii'ig rod or shaft, (32, and is provided on its outer end with anupwardly extending and angularly bent arm, 63. A coil spring, 64, isinterposed between and connected to :1 depending arm, 57, and theupwardly extending arm, 63, for the purpose of preventing the accidentaldisplacement of the dog, 59, with respect to the arm, 60.

Pivotal-1y mounted upon a rod or shaft, 67, which is supported betweenthe end plates, 10 and 11, is a plurality of pawllifting arms, 68, onefor each column-of keys, as is clearly. illustrated in Figure 3 of theaccompanying drawings.-;Eaeh of the arms, 68, is providedwith a pairofdownwardly bent ears orlugs, 69, which form the' pivotal connectionbetween the rod .or shaft, (37. The forward end of the arin, (38-, isbent.downwardly, as .at 70, which-is provided with-a horizontally:disposed and angularlybent ledge: or extension, 71, for the purpose ofeontactin =Wil!l1 and lifting the down-pawl, .48, out o ,engagement'withthe ratchet teeth,30,gformed upon theupper edge of themamcontrol piece.The rear end, 72,, of thepawl-liftiirgarms issIightly hentdownwardlyandjsadapted to be, engaged by the-forward end, 7 .5 of abell-cranl:member; 76,- ,or, which. might be termed, a cancelling-release armsThebeH-erank lever,

.T6,. is secured tothetransversely extending perextremity with a,rounded nose, 4 5. -,-..lt;;is

tobe, understood, of course, tha-t,,th e arms, 4-2 -and 44,-,arestamped,.,o r'= otherwise: interod or, .-;shaft,.- 77, which is.s'imilarl y 5constructed' andl mounted asiis the shalt, 58.

. The downwardly extending arm,- 1'8, of the lever, T6, is adapted, t0,be engaged by the z upwardly extending .arm, ,63, which lS,- of

course, integrally formd with the an til'ariy bent pawl, til, which, forthe sake 9 clearuess, I may term a stop-hook iewer, The pawl, 61, isalso in alignment-with the main control piece, -28, that, at apredetermined period, as .willi be Q hereinafter fnrther. de-

scribech'tlrispawlfmay be engaged by the notch or depression, 36.'lherebeing but one-belherank memberyTG', it is obvious that theremainder of the forwardly extending plates, 75,-. need not be providedwith depending arms,78. .r

Again referring to the pawl-lifting arms. (58, it will be noted withparticular reference to Figures 3 and 12, that I have provided anoutwardly extending and integrally formed lug or projection, 80, whichis adapted to engage at certain intervals theledge Int) or reducedportion, 81, formed on the upper end of a vertically extending andrelatively narrow arm, 8&3, which is mounted to oscillate upon a.transversely extending rod or shaft, 8 3. This arm, 82-, is provided atits lowermost edge with a substantially horizontal arm, 84. which bentupwardly to provide the arm, 85. The upper end of the arm, 85, is inline with the nose, 35, of the main control piece, 28, and is adapted tobe engaged thereby at predetermined intervals for rocking the arm, 82,whereby the lug, 80, will be disengaged from the ledge, 81. I provide acoil spring, 86, which is secured near the lower end of the arm, 82, andits opposite end to the stationary rod, 88, for the purpose of causingthe ledge, 81, to bear against the lug, 80.

A spacing rod or bar, 87, is provided with shoulders and reducedportions at their upper and lower ends, which are loosely mounted insuitable openings in the'pawllifting arm, 68, and the lower or up-pawl,49, so that they will have the same relative movement. A coil spring,86, is interposed between and connected to the tip-pawl, 49, and thepawl-lifting arm, 68, for the purpose of applyin tension on theshoulders of each end of the spacing member, 87,

whereby the relative movement of thesemembers will be assuredf 7 Againreferring to the rounded'nose portion, 45, formed upon the uper' end ofthe diagonally extending arm, 44, which is adapted to, at all times,support the pawllifting arm, 08, by hearing against the lower sidethereof, I accomplish-this continuous contact by means of a coil spring,90', which connected at one end to the pawl-lifting device and itsopposite'end, to the relatively stationary rod or shaft, 51, as 18clearly lllustrated in Figures 4, 5, and 6. For the purpose ofpermitting the downpawl, 48, to bear against and engage the teeth, 30,'of'the main' control piece and to 'yieldingly retain this-pawl in itsforward position by reason of the fact that the rod or shaft. 50, ismountedin an elongated'slot,

54,1 provide a relatively short coil spring,

92, and secure it. at one end to the relatively stationary shaft, 67,and its opposite end to the lug, 93, which is preferably bent up" wardlyfrom the rearward end of'the downpawl, 48.

' For the purpose of permitting the usual lock control lever, 40, tooscillate a predetermined distance about the rod or shaft, 95, I--

provide a downwardly extending lug, 96, which is adapted to pass throughan opening, 97, suitably formed in that portion ofthe stationary frame.The cut-out portion, 98, formed in one edge of the depending lug, 96, asis illustrated in Figures 4, 5 and 6, will, of course, permit thismovement. The lock control lever, 40, is yieldingly held in its normalposition, as is shown in Figure 4, by means of the coil spring, 100,which has one end thereof connected to the arm, 42, and its other endsecured to the transversely extending stationary rod, 88.

Referring now particularly to Figures 1 and 2, which indicate generallythe resetting mechanism in connection with the usual resetting arm, 105,106 indicates a slidably mounted lever, having a downwardly andoff-setportion, 107. A rocking lever, 108, which is pivoted in itsapproximate center as at 109, is pivoted at its lower end to the off-setportion, 107, and has pivotally mounted to its upper end one end of alink, 110. The opposite end of the link is pivotally connected to thelower end of an os cillating lever, 111, which is, in turn, rigidlylever, 106, and the pawl, 113, The rod, 83,

may be extendedibeyond the outer edge of the plate, 10, for the purposeof limiting the rearward movement of theslidably mounted --lever," 106,supplemental to the slot and bolt,

101- and 102. T Q The automatic release for the purpose of moving -the'-lever, l06',"a predetermined distanc'oi}"sufiiciently' to actuate thecancelling release arn'f, {76; whichwill "raise the downpawl- 34 throughthe medium of the pawllifting min," as; is; indicatedfgenerally as at112. A dog dr"pawl, 113,- ispi-votally mount- "fed to the forward end'ofthe'lev'er, 106, and

is provided 0n"'it"'s up'per end with an angularly disposed'?stop",-11'4, which'is adapted to bear aga in'st 'thehub por'tion 115', commontothis ty eof calculating machines. Formed "intgra ly-"with thearm,114,"fis a rearwardly extending portion, 116, for 'the purpose ofsupporting one" end of a coil spring, '117,' whose opposite end issecured to a gelativlystationary arm, 118, which i's'carri'ed bythefo'rward end of the lever, 106i k}transversely-extending pin,'-"119,is secured to therear end'of theshding lever,

"120', and its upper endis flattened for the purpose of '-more readilyengaging the toothed portion of thepawl or dog, 113.

When the lever, 120, is moved forwardly through themedium of the handresetting arin, 105, to which it is, of course,'pivoted, the pin, 110,will pull the dog or pawl, 113, forwardly and continue until theupwardly extending arm, 114, comes in contact with the hub portion, 115,when a continued movement of the lever,-120, will cause the upwardmovement of the dog. 113, about its pivot, 121. The pawl, 113, will nowbegin to be moved upwardly and be freed from the pin, 119, and bereturned to its normal position as is shown inFigure 1 and as isillustrated in dotted lines in Figure 2 of the accompanying drawings.

The audible signal, which is associated with my improved key-lockingmechanism and which is clearly illustrated in Figure 11 of theaccompanying drawings, together with the diagrammatic illustrationsshown in Figures 4, and 6, consists of a hell or other audible device,124, which is securely mounted on the inner side of the plate, 11. Onthe flattened side of the rock-shaft, 62, I securely mount the hammer,125, so that it will normally be spaced from the bell, 124, as is shownin Figures 4, 6 and 11 and which is adapted to strike the bell theinstant the operator releases the downward pressure upon the key, 15,unless he has completed the full downward oroperntive stroke.

Operation.

In the operation of my automatic control and audible andvisible signal,as when the key, 15, is depressed by the operator, it comes in contactwith the main; lever which pulls the main control lpiece, .28,-forward,-

pivot,:95, thus raising the rearward end, 43,

and theangular arrn,i44,=of= thei arm, 42. The upward. movement ofthe-end, 45, of the arm, 44, lifts the pawllifting. arm, 68,sufticiently to'raise the down-p'a-wl,;48, to disengage it from theratchet teeth, 30.; ;At this timethe downspawl disengage support, 82, is1 permitted to rock forwardly about its pivot,

83, to permit the ledge, .81, to-engage beneath the extension,- 80, ofthe pawl lifting arm, 68, and hold it in its elevated position, asisclearlyshown in Figure- 6.

13yreason of the spacing rod, 87, being supported between the pawlliftingarm, 68,

and the tip-pawl, .49,the.raising of the-arm,

68, of course, permits the pawl, -49, to corre- -spondingly raise, byreason of the coil spring, 86. In this manner, the up pawl,

49, engaging the ratchet-teeth, 31, on the under side of the maincontrol piece, 28, prevents the depression of said key until a full upstroke has been completed.

When the operator, after partially depressing a key, 15, removes hisfinger therefrom, the key returns a very slightdistance upwardly, whichupward movement simultaneously locks all of the keys in the severalcolumns, and in addition thereto sounds the audible signal, 124. This isaccomplished by means of the down-pawl, 48, which, haw

ing been in a sliding engagement with the ratchet teeth, 30, of the maincontrol piece, 28, is now engaged by one of the teeth, 30, and pushedrearwardly against the tension of the coil spring, 92.

The rearward movement of the pawl, 48, is comparatively very slight andis limited, of course. by the elongated slot. 52, with respect to theshaft, 50, upon which the pawl is mounted. The slight rearward movementof the down pawl, 48, is sufficient to cause the downwardly bent end,55, thereof, to engage the arm, 56, of the control lever stop hookrelease, 57, and rock the rod or bar, 58. The rocking movement of thedog, 59, is sufticient to release the lever stop hook, 61, and cause theshaft or rod, 62, to rock slightly. \Vhen the lever stop hook, 61, hasmoved downwardly, all of the columns of keys will be effectively lockedby reason of the fact that a lever stop hook is provided for eachcolumn, all being mounted upon the same rock, 62. and are adapted toengage the cutout portions, 36, formed in the upper end of each of themain control pieces. As has been already explained, the hammer, 125,will, at this moment, strike the bell, 124, and sound the audible alarm,which will permit the operator to glance at the key board, and readilycomplete the operation by the continued downward pressure of thepartially depressed key, 15. The fact that the key, which has beenpartially depressed indicating an incomplete stroke, remains in thatposition instead of returning to its normal or.- in itial; position, ofcourse, provides 'avisible signal for the operator.

When the partially depressed key, 15, is f-nrthendepressed. to completethe, operative stroke, thdrockingLmovementof the lock control, lever,,40, .lifts the pawl. lifting arm, 6 8,..disenga'ges;thedown-pawl, 48,from it locked position with respect to its teeth, 30, and-the end, 43,ofgthe arm, 42, lifts the lever stop hook, 61, rocks-the shaft, 62, anddisengages and unlocks the several columns of keys,

- .What I-claim.is: 1..In= a keyboard-calculating in:u-.hine,.a

plurality of rows of keys,'locking' means common to'each of the keys.for all rows and arranged with respect to the keys so that the partialdepression. of any one of said keys will look all the keys in theremaining rows upon release of pressure from said partially depressedkey and means associated with said keys whereby the completion ofdownward pressure upon the partially depressedkey will unlock all thelocked keys.

2.- In akeyboard calculating machine, a

plurality of rows of keys, locking means common to each of the keys forall rows and arranged with respect to the keys so that the partialdepression of any one of said keys will simultaneously lock all the keysin the remaining rows upon release of pressure from said partiallydepressed key, and means associated with said keys whereby thecompletion of downward pressure upon the partially depressed key willsimultaneously unlock all the locked keys.

3. In a keyboard calculating machine, a plurality of rows of keys,locking means common to each of keys for all rows, and arranged withrespect to the keys so that the partial depression of any one of saidkeys will lock all the keys in the remaining.

rows, said locking means including a relatively movable toothed memberand coacting pawl associated with the keys for retaining the partiallydepressed key in its lowered position.

4. In a keyboard calculating machine, a plurality of rows of keys,locking means associated with each of the keys for all the rows andarranged with respect to said keys so that the partial depression of anyone of the keys will lock all the keys in the remaining rows uponrelease of pressure from the partially depressed key said locking meansarranged to retain said key in its locked position, and movable meansfor unlocking said remainder of keys when the partially depressed keyhas been fully or operatively depressed.

5. In a keyboard calculating machine, a plurality of rows of keys,locking means common to each of thekeys for all rows.

and arranged with respect to the keys so that the partial depression ofany one of said keys will lock all the keys in the reniaining rows, andmeans associated with said keys whereby the completioniof down wardpressure upon the partially depressed key will unlockthelocked keys saidlocking means includin mechanism for retaining said partially (fepressedkey in its partially depressed position.

(3. In a keyboard calculating machine, a plurality of rows of keys,locking ,means common to each of the keys for all rows and arranged withrespect to the keys so that the partial depression of any one of saidkeys will lock all the keys in the remaining rows, said locking meansincluding mechanism associated with the keys for retaining the partiallydepressed key in its lowered position.

7. In a keyboard calculating machine, a plurality of rows of keys,locking means common to each of the keys for all rows and arranged withrespect to the keys so that the partial depression of any one of saidkeys will simultaneously lock all the keys in the remaining rows, andmeans associated with said keys whereby the completion of downwardpressure upon the partially depressed key will simultaneously unlock thelocked keys, said locking means including mechanism operated by saidpartially depressed key for retaining it in its partial key-strokeposition.

8. In a keyboard calculating machine, a plurality of rows of keys, meansfor automatically locking all the keys in the remaining rows by thepartial depression of any one of said keys and means whereby the saidremainder of keys will be automatically unlocked by the completedepression of said partially depressed key, said automatic locking meansincluding mechanism associated with the keys for retaining the partiallydepressed key in its lowered position, said partially depressed keybeing subject to detention to various depths thereby providing a visibleindication of the partially depressed key.

9. In a keyboard calculating machine, a plurality of rows of keys,locking means common to each of the keys for all rows and arranged withrespect tqthe keys so that the partial depression of any one of saidkeys will lock all the keys in the remaining rows, said locking meansincluding mechanism for retainin the partially depressed key in itspartial keystroke position thereby providing a visible indication ofsaid last named key, said partially depressed key being. subjecttodetention to various depths and means associated with said keys wherebythe completion of downward pressure upon the partially depressed keywill unlockall of said locked rows of keys on the keyboard.

10;, In a key board calculating machine, a

plurality of rows of keys, means whereby the;

partial depression of' anyone .of thekeys will automatically lock, theremaining rows of keys, said means including a key control lever havingnotched portions outwardly ex tending lugs carried byeach' of said keysadapted for engagementby said notched portions, and mechanism associatedwith and operated by said key control lever for retaining it in itspartial key-stroke position.

11. In a keyboard calculating machine, a plurality of. rows of keys,means whereby the partial depression of any one. of the keys willautomatically lock the remaining rows of keys, said means includinga keycontrol lever having hook portions, outwardly extending pins carried byeach of said keys adapted for engagement by said hook portions andmechanism associated with and operated by said key control lever forretaining it in its partial key-stroke position, and means forautomatically unlocking said remainder of rows of keys operated bycompletely depressing the partially depressed key.

12. In a keyboard calculating machine, a plurality of rows of keys, eachof said keys havin a single key stem and a unitary head carrieu thereby,locking means common to each of the keys for all rows and arranged withrespect to the keys so that the partial depression of any one of saidkeys will lock all the keys in the remaining rows, said locking meansincluding mechanism for retaining said partially depressed key in itsvarious stages of its lengthwise movement, and means associated withsaid keys whereby the completion of pressure upon the partiallydepressed key will unlock all said locked rows of keys on the keyboard.

13. In a keyboard calculating machine, a plurality of rows of keys,locking means common to each of the keys for all rows and arranged withrespect to the keys so that the incomplete depression of any one of saidkeys will lock all the keys in the remaining rows said locking meansincluding mechanism operated by said partially depressed key forretaining it in its partial key-stroke position thereby providing avisible Indication of an incomplete keystroke, and an aud'i'ble signal,said visible indication occurring simultaneously with the operating ofthe audible signal and the lockin' of said remaining rows of keys on thekeyboard;

key for retaining it in its partial key-strokeposition thereby providinga visible indication of an incomplete key-stroke, an audible signal,said visible indication occurring simultaneously with the operating ofthe audible signal and the lockin of said remaining rows of keys on thekey board, and means associated with said partially depressed keywhereby the completion of downward pressure upon the partially depressedkey will unlock all of said locked keys on the keyboard again placingthe machine in its operative position.

15. In a keyboard calculating machine, a plurality of rows of keys,locking means common to each of the keys-for all rows and arranged withrespect to the keys so that the incompleted depression of any one ofsaid keys will lock all the keys in the re maining rows, said lockingmeans including mechanism operated by said partially de pressed key forsimultaneously retaining it in its partial key-stroke position therebyproviding a visible indication of the incomplete stroke, an audiblesignal, said audible and visible indications being simultaneous, andmeans associated with said keys whereby the completion of a downwardpressure upon the partially depressed key will unlock all said lockedrows of keys on the entire keyboard, returning the keyboard to itsoperative position.

16. In a keyboard calculating machine, a plurality of rows of keys,locking means common to each of the keys for all rows and arranged withrespect to the keys so that the partial de )ressiou of any one of saidkeys will lock a l the keys in the remaining rows, and said lockingmeans including mechanism associated with the keys .for retaining thepartially depressed key in its lowered position thereby providing avisible indication of said partially depressed key, said partiallydepressed key being subject to detention to various depths.

17. In a keyboard calculating machine, a plurality of rows of keys,means associated with the keys for retaining a partially depressed keyin its lowered position, locking means common to each of the keys forall rows and arranged with respect to the keys so that the partialdepression of any one of said keys will lock all the keys in theremaining rows, each row includin a key control lever, a main controlmember operatively connected thereto, a movably mounted bar having meanscarried thereby adapted to engage said main control members for lockingall of said remaining rows, and means for unlocking all of said lockedkeys on the keyboard operable by the completion of down- Iyard pressureupon said partially depressed 18. In a keyboard calculating machine, a.plurality of rows of keys, means associated with the keys for retaining"a. partially depressed key in its -lowered position, lockingmeanscommon to each of thekeys for-all rows and arranged with respect tothe keys so that the partial depression'oi any one of said keys willlook all the keys in the remain ing rows-each row including a keycontrol lever, -a main control member operatively connected thereto andprovided Wllill a cutout portion and atransversely extending and movablymounted shaft havinga plurality of pawls arranged to 'cnga e the cut-outportions in said main contro members, and means for unlocking all ofsaid locked keys on the keyboard 'operably by the completion of downwardpressure upon said partially depressed key.

19. In combination with rows of keys in a keyboard calculating machine,latching devices common to each row of keys normally in inoperativeposition for retaining the keys in each of the rows from depression,means for releasing said latching devices by incompletc depression andrelease of a key and for holding said key from rising from itsincompletely depressed position includin a key control lever and a maincontrol mem r operatively connected thereto, and having a toothedportion engaged by said latching devices, said releasing means havingprovision for retaining said partially depressed key in its loweredposition, and means for resetting the latching devicesto inoperativeposition by complete depression of said key.

20. In combination with rows of keys in a keyboard calculating machine,latching devices common to each row of keys normally in inoperativeposition for retaining the keys in each of the rows from depression,means for releasing said latching devices by incomplete depression andrelease of a key, and for holding said key from rising from itsincompletely depressed position includin a key control lever, and a maincontrol member operatively connected thereto and having provision forretaining the partially depressed key in its lowered position, and meansfor resetting the latching devices to inoperative position by completedepression of said key.

21. In a calculating machine having a plurality of rows of keys and akey control lever for each row, the combination with latching devicesfor engaging said control lever to hold the keys fromdepression andcomprising a transversely arranged movable shaft and pawls carried bysaid shaft and adapted to engagethe control lever, means arranged forrelease by incomplete ,depression of a key for moving said shaft andpawls into operative position and means operated by complete depressionof said key for restoring said shaft and pawls to inoperative position.

22. An attachment for a keyboard calculating machine'having a pluralityof rows of keys, comprising latching devices common to each row of keysnormally in inoperative po sition for retaining the keys in each of therows 'from depression, means for releasing said latching devices byincomplete depression and release of a key, and for holding said keyfrom rising from its incompletely depressed position, and means forresetting the latching devices to inoperative position by completedepression of said key.

23. An attachmentfor a keyboard calculating machine having a-pluralityof rows of keys, comprising locking means common to each of the keys forall rows and arranged with respect to the keys so that the partialdepression of any one of said keys will lock all the keys in theremaining rows upon release of pressure from said partially depressedkey, said locking means including means for retaining 'said partiallydepressed key in the various stages of its lengthwise movement, saidretaining means including mechanism for controlling the upstroke of saidpartially depressed key when fully depressed and means associated withsaid keys whereby the completion of pressure upon the partiallydepressed key will unlock all said locked rows of keys on the keyboard.

- JOHN H. F. SILVER.

